50% for front windscreen? you'll have trouble driving at night for sure.. JPJ regulations aren't for sucking your money, they are for safety. Too dark on the windscreen will give reduce your visibility.

cheap or expensive, make sure the front is more than 70% VLT, and other windows 50% VLT.
of course, we cannot be sure about the spec, but at least if JPJ kacau, the shop will be responsible - you can claim from them or let they settle the summons for you, simply because they claim that their tint is 'JPJ approved'..